42 
for the eccentricity. The readings were immedeately recorded on punched cards 
and checks and computations were programmed. The scale of the co-ordinates is 
defined by a 2 m invar bar. The instrument used was a Wild T3 theodolite. 
The overall accuracy of the co-ordinates is estimated as a spatial standard 
error vector of 0.07 mm. 
8.1.2. Fiducial transformations 
The corners of the picture were used as fiducial marks. Their so-called given 
co-ordinates were simply measured on an arbitrarily chosen picture. Even 
though these co-ordinates are not free from error, they still serve as a defini 
tion of the image co-ordinate system. The main results of the computations are 
shown in Table 4. Using Bartlett’s test 1 ) on the standard errors of unit weight 
Fig. 9. 
The basement ’’cage”. The points form pyramids as in Fig. 8 to suit normal angle and wide 
angle cameras. The plane close to the wall contains a large number of evenly distributed 
points. 
l) This test is used to examine the homogenity of a series of variances. See Kendall-Stuart 
[21], example 24.4.